One presently known method of making hoses that include a synthetic rubber tube and a covering of reinforcing and/or protective material is to extrude the rubber core tube onto a mandrel, apply the covering, envelope the covering with a lead sheath, and subject the entire assembly to vulcanization in a steam chamber. Vulcanizable rubber adhesives or bonding agents such as rubber cement or uncured calandared rubber sheet may be interposed between the tube and covering and generally are interposed between layers of a multi-layer covering. This material becomes cured during the vulcanization of the assembly to bond the various constituents of the hose together, during the vulcanization of the synthetic rubber tube.
The bond between the different braids and synthetic rubber core tube achieved with this method has not been completely satisfactory or reliable and it has been difficult to hold the inside and outside diameters of the core tube to precise limits because of the application of the braid layers before complete curing of the rubber core tube. The processes involved require considerable investment in equipment for applying and stripping the lead sheath and for effecting vulcanization. The melting of lead and the handling of large amounts of lead also entail medical and physical hazards for the workmen involved.